Pump assemblies



April 29, 195s M. L. EDWARDS PUMP ASSEMBLIES 4 Sheets-Sheet l Filed March 23, 1955 April 29, 1958 M. L. EDWARDS 2,332,292

` PUMP AssEMBLIEs Filed March 23, 1955 4 sheets-sheet 2 April 29, 1958 M. L. EDWARDS PUMP ASSEMBLIES 4 Sheets-Sheet 3 Filed March 25. 1955 .ML/@.5 Lau/fel! Edwards April 29, 1958 M. L. EDWARDS PUMP ASSEMBLIES 4 Sheets-Sheet 4 Filed March 23, 1955 5 NN r .m JM w@ A.. .Nh *M /J W 6 w M A m S W (i EN .Wi N

United States Patent` PUMP ASSEMBLIES p Miles Lowell Edwards, Portland, Greg. Application March 23, i955, Serial No. 496,268

13 Claims. (Cl. 10S-87) This invention deals with pump assemblies having standardized body parts adapted to receive diderent types of pump components for producing pumps capable of meeting widely different specifications. More particularly, this invention deals with fuel booster pumps for jet type airplane power plants wherein pump components can be substituted as required to meet the demands of a particular jet engine to insure adequate fuel delivery when the airplane climbs with hot fuel from sea level up through intermediate altitudes where dissolved air is released by the fuel to the highest operating altitudes where actual boiling of the fuel occurs.

The invention will hereinafter be described as embodied in a submerged type fue] booster pump for mounting in the fuel lcell of a turbo-jet aircraft fuel system but it should be understood that the principles of this invention are generally applicable to pumps, especially of the vapor separating type and, therefore, the scope of this invention is not limited to any speciiic usage of the pump.

According to this invention, `a standard main pump casing and mounting base is arranged for selectively receiv ing different types of pump impellers designed to meet different specications, different types of electric motors for driving the impellers, and auxiliary vapor diffusing units to augment the vapor separating capacity of the pump. The standard pump casing and mounting base includes a base plate adapted to cover an opening in the bottom of a fuel cell and be bolted to said bottom. rfhis base has opstanding legs supporting an annular pump casing with a volute chamber surrounding a central impeller chamber. The volute chamber has a peripheral outlet integrally cast with an upstanding coupling member on the base plate. This coupling member opens through the base plate and is adapted to receive a, pipe fitting on the outside of the tank. The pump casing provides an axial inlet or eye spaced just above the base plate. ladially extending diffuser passages are formed in the casing immediately adjacent the `axial inlet. These passages act as a secondary inlet or alternately, as a vapor discharge outlet, depending upon the rate of iiow through the pump. The pump casing is adapted to receive various types of motors which are secured to the top wall of the casing and these motors carry different types of impellers designed for meeting various specitications. The impellers operate in an impeller chamber in the pump casing. The motors are arranged with end heads that carry impeller hub bearings which project into `the pump casing to surround the impeller hub. In order to meet high vapor separating demands, the motor casing is adapted to carry a secondary diffuser attachment cooperating with the top of the pump casing.

While jet engine fuel is less volatile than the high test gasolines used for piston aircraft engines, the altitude range of jet engines and the rate of climb of such engines, is so much greater than piston driven aircraft engines, that even the less volatile jet engine fuel, unless confined in a pressurized tank, will jrelease dissolved air and will ice 2 boil within the altitude range of the aircraft. Further, jet engines consume less fuel at high altitudes in proportion to the fuel requirements for the same speeds at lower altitudes and efcient pump design should, therefore, avoid a power wastage in pumping fuel beyond the demands of the engine. in addition, the rapid rate of climb a engine, enhances the problem of release of dissolved air from the fuel before the fuel actually begins to boil at the higher altitudes. The pump must be capable of getting rid of the released air while still `supplying enough fuel to permit the aircraft to climb at hi i Since release of dissolved air is not initiated until altitudes are reached Where the fuel demand is less than the takeoff demand, the pumps of this invention effectively utilize auxiliary inlets as air outlets when the flow rate demand decreases.

,t is then a feature of this invention to provide the most efficient, lightest and most compact booster pump assembly for meeting a particular specification Without, however, altering the basic design of the pump.

Another feature of this invention is to provide a high speed fuel booster pump assembly which is streamline to meet the requirements of a particular engine without wasting power. This invention thus avoids the hereto fore followed general practice of overdesigning the pump to meet the most rigid specifications and then using this pump for engines not having such stringent fuel demands.

An object of the invention is to provide fuel booster pump units with standardized housing and mounting parts together with a series of special components fitting the basic parts to cooperate therewith for meeting particular specifications. i

Another object of the invention is to provide a fuel booster pump for jet engines having a standardized mounting base, inlet and pump casing, together with a series of components for the standardized parts which will cooperate therewith to impart different characteristics to the resulting pump. i

A still further object of this invention is to provide a jet engine fuel booster pump for submerged mounting in a fuel cell wherein the pump casing is arranged to selectively receive components which will cooperate therewith to produce a pump capable of delivering the required fuel ilow to the jet engine and capable of removing air and vapors within the operating altitude range of the engine without consuming power in Waste recirculation and vapor removal action beyond the demands of the engine.

A general object of the invention is to provide pump assemblies designed for a wide variety of altitude pumping conditions without involving 'wastage of operating power.

A specific object of the invention is to provide a fuel booster pump having a basic high speed hydraulic design to emciently deliver high rates of fuel and to selectively add to said design components which will increase the vapor separating capacity of the pump.

A further object of the invention is to provide a telescoped impeller hub, motor shaft and bearing arrangement for pumps which reduces the required overall pump length, minimizes support weight and increases resistance to deiiection whereby the pump is especially adapted for vertical mounting in thin airplane wing tanks.

A further object of the invention is to provide a new pump impeller which is drawn up tightly against the supporting shaft adjacent the surrounding shaft bearing for increasing the rigidity of the impeller mounting in a pump.

Another object of the invention is to provide a booster pump having a main inlet supplying liquid to an impeller chamber and a diffuser outlet immediately downstream from the inlet surrounding the impeller in the chamber g to act as a secondary inlet at high rates of flow through assenso A the pump and as a vapor and air outlet at lower rates of flow.

A further object of the invention is to provide a vapor separating pump capable of swallowing gas and air bubbles at high rates of flow where these bubbles cannot create a vapor lock and capable of efficiently separating the bubbles from the liquid before the liquid becomes trapped in a feed line whenever the rate of ow is low enough to permit accumulation of vapor and air which might disturb normal pump operation.

Another object of the invention is to provide a fuel booster pump which will deliver high rates of flow at low altitudes at high efficiency, will supply intermediate rates of liow at intermediate altitudes while removing .air bubbles which are released from the fuel at these altitudes and will supply relatively small rates of fuel flow at still higher altitudes where boiling of the fuel occurs while effectively separating vapors from the boiling fuel.

Other and further objects of this invention will be apparent to those skilled in this art from the following description of the annexed sheets of drawings which, by way of preferred examples, illustrate several embodiments of the invention.

On the drawings:

Figure l is a vertical cross-sectional view, with parts in elevation, of a jet engine fuel booster pump assembly having components designed for high speed operation with nominal gas-removing capacity.

Figure 2 is a horizontal cross-sectional view taken along the line Illll of Figure l.

Figure 3 is a bottom end view of the impeller in the pump of Figure 1.

Figure 4 is a side View of the impeller of Figure 3.

Figure 5 is a bottom end view of an alternate impeller for the pump of Figure l to increase the vapor removing capacity of the pump.

Figure 6 is a Side view of the impeller of Figure 5.

Figure 7 is a top View of the impeller of Figure 5.

Figure 8 is a vertical cross-sectional view of a further pump assembly of this invention showing departures from f the pump of Figure l to further increase the vapor separating capacity of the pump to accommodate higher altitude performance of the pump.

Figure 9 is a horizontal cross-sectional view taken along the line lX-IX of Figure 8.

Figure l0 is a bottom end view of the impeller of the pump of Figure 8.

Figure ll is a vertical cross-sectional view of an alternate motor and impeller assembly for the pumps of Figures l and 8.

Figure l2 is an exploded somewhat diagrammatic elevational view illustrating the manner in which the various pump components can be assembled in the standardized mounting base and casing to produce the pumps of this invention.

As shown on the drawings:

As shown in Figure l', the submerged fuel booster pump 10 is basically composed of a mounting base and pump casing part 11, a cover or end head part l2, a motor casing 13, and an impeller 14.

The part 11 includes a flat plate-like base 15 with apertures 16 therethrough around the periphery thereof. The plate underlies the bottom wall 17 of a fuel cell or tank and covers an opening or hole 18 through this bottom wall. A mounting ring il@ is mounted on the bottom wall 17 around the hole 18 and is tapped to register with the holes 16 around the periphery of the plate 15. Mounting screws 20 threaded into the tapped holes of the ring 19 extend through the bottom wall i7 and through the apertures 16 to mount the unit l@ in the fuel cell.

The base 15 has a depressed portion 21 with a central boss 22 carrying a drain plug 23. This depressed portion 21 provides a sump S below the bottom i7 of the fuel cell. Legs 24 extend upwardly at intervals from the all `- 2d of the pump casing 25 to provide a projecting ddepressed portion 21 of the base plate 15 to support an annular pump casing 25 in spaced relation above the bottom of the sump.

The pump casing 25 is a generally annular body with an axial inlet throat Z6 communicating with the sump S at a level below the tank wall 17 so as to be submerged in fuel from the tank even when the tank is substantially empty. The inlet 2-6 is cylindrical and preferably has an outwardly dared or beveled mouth 26a, for smooth flow to the inlet. The cylindrical wall 26 of the inlet is intersccted by piurality of diffuser passages 27 which extend radially outwardly and axially downwardly from the inlet to the generally cylindrical periphery 28 of the pump casing. An upwardly curved lip 29 is formed around the periphery 28 below the passageways 27 for directing discharge from the passageways away from the inlet 26.

As shown in Figure 2, the passageways 27 are separated by ribs 30 providing diifuser vanes. The passages 27 thus have inner ends in advance of the outer ends to diffuse a centrifugally whirling flow from the varies of the impeller .114 to a laterally outward ow over the lip 29 at a relatively high velocity.

The cylindrical inlet 26 tapers outwardly above the passages 27 as illustrated at Zeb in Figure l to provide a gradually widening passage. The upper end of the portion 26h merges into a widely beveled or flattened wall 26e having a substantial horizontal component. An annular volute chamber 31 surrounds the wall 26e so that the inlet 26 discharges into the volute and is in full con munication therewith around the entire inner circumference of the volute chamber.

The volute chamber 31 has a peripheral outlet conduit 32 extending from the periphery 28 of the casing Z5 to an inverted bell-shaped coupling 33 on top Vof the plate l5 and having an open bottom end bounded by a rim flange 34 on the bottom of the plate. The top of the coupling 33 has an internally threaded boss 35. An l-- shaped pipe coupling 36 snugly fits in the rim 34 and has a boss 37 receiving a bolt 38 therethrough which is threaded into the boss 35 to draw the coupling 36 tightly against the gasket 39 between the bolt 38 and the coupling thereby uniting the parts. The volute chamber thus discharges to the pipe coupling 36.

The pump casing 25 has a at top 39 with a cylindrical aperture 4l) therethrough aligned with the inlet 26 and terminating at the volute chamber 31. The top wall 39 is tapped at intervals to provide screw holes such as il around the opening 4t).

A screen 42 surrounds the periphery 28 of the casing 25 and is bottomed on the side wall of the depressed portion 21 of the base l5 to surround the passages 27 and the inlet 26 so that fuel from the tank must be screened before it enters the sump and reaches the passages or the inlet.

The cover or end head l2 of the pump assembly ll) is composed of a flat plate-like portion i3 overlying the top wall 39 of the pump casing and apertured at intervals to receive mounting screws 44 threaded into the holes lll. This plate portion 43 extends beyond the periphery ange. The plate has an integral thickened central portion or head .55 snugly fitting through the bore or aperture 4d in the top of the pump casing and projecting into the upper portion of the volute cavity 31 to form a cylindrical inner periphery for the cavity. The head 4:3 has a flat bottom i6 with a central cylindrical aperture 47 extending to a radial shoulder 48 which terminates at a larg-:r diameter bore 49 extending through the head to a counterbore 5t? through the plate portion 43. A well is thus provided in the head 45 and has an open bottom t7 with a shoulder d8 surrounding this open bottom.

A groove 5l is formed around the head 45' to register with the wall of the aperture titi. This groove 5l is joined with the volute 3l through a bleed hole 52 in the pump casing and is joined with the top of the plate 43 through E? a bleed hole 53. Fluid from the pump casing will, therefore, be bled through the plate to ilood the motor Casing for lubricating the motor bearings and cooling the motor.

A bushing sleeve 54 is press fitted into the bore i9 of the head i5 and is bottomed on the shoulder 4%. A carbon bearing ring :3S is carried in the bushing 54 and is also bottomed on the shoulder /i-i. lf desired, the carbon bearing `could be replaced with any other suitable bearing ring or with an anti-friction bearing assembly.

rlhe motor part i3 is composed of a enerally cylindrical casing S6 with an outturned iiange t the bottoni thereof apertured at intervals to receive fastening screws 58 which are threaded into the extended flange portion ot' the plate 0.13 thereby uniting the part 'l2 to the casing i3.

The top of the casing S6 also has an outturned 59 therearound and a cover plate 50 on the top the casing S6 is apertured around the periphery thereof to receive fastening screws 6l threaded into the flange 59. This co er plate 60 has a cup-shaped raised central por tion 62 providing a recess d3. depends from the cover portion to provide a cylindrical bore 65 in the cover carrying a bushing sleeve 66 which is bottomed on a shoulder 67 between the bore 65 and the recess e3. A carbon bearing ring or'other suitable bearing 68 is mounted in the bushing 66. A screened port l is provided in the plate 60 to vent the interior of the motor casing to the tank so that 'luid from the bleed hole 53 can be circulated through the motor casing.

A hollow motor shaft 69 has one reduced end 69a thereof rotatably mounted in the bearing ring :'55 carried by the end head l2 and a second reduced end 6% rotatably carried in the bearing ring 68 mounted in the end cap 60. An integral collar portion 70 on the shaft provides a shoulder overlying the bearing ring 55 to thrust thereagainst. A shoulder 'lon the upper end of the shaft bottoms a washer 72 thrusting against the bearing ring o8. The shaft is thereby rotatably supported in the bearing rings 55 and 68 and is held against axial shifting by the thrust collar 7@ and washer 72.

A thickened portion 7d in the shaft dit above the collar 'ill provides a reduced diameter splined bore '75 and a ilat top shoulder 76. A self-locking nut 77 bottomed on the shoulder '76 has a splined portion 7S anchored against rotation in the bore 7S. A relatively thin mounting bolt 79 is threaded into the nut 77 and depends into the inlet mouth 26 of the pump casing.

A motor armature d is secured around the shaft 69 and a motor held winding El is mounted in the casing 56 to surround the armature titl. The shaft 69 is thus driven by the resulting motor.

As shown in Figures 1, 3 and 4, the impeller ld has a hub S2 snugly fitting in the open bottom end of the shaft 69. A key 53 carried in a groove in the hub 32 is seated in a groove tlfl of the shaft o@ to join the hub and shaft for co-rotation. The mounting bolt 79 extends through the hub and has its head thrusting against the underface of a disk-like impeller head 85 tting freely in the aperture 47. The bolt draws the head tightly against shims or a washer Sti on the bottom of the shaft 69. The tensioned bolt lirmly holds the head 8S in thrusting relation with the end of the shaft which is surrounded by the bearing S'. The shims @d provide the desired clearance between the impeller and the bottom wall do of the head 45. The telescoped hub port 5d provide a iirm support for the impeller without occupying any appreciable vertical space. A firm, rigid, lightweight, compact impeller support is thus provided.

Five lingers 85a radiate from the bottom of the head SS in spaced spiral paths and pumping vanes 87 depend from the lingers. Each vane 87 has a sharp inner leading edge 87a sloping to the head 79a of the bolt 79 along a beveled path simulating the drainage path of liquid through an opening thereby accommodating smooth flow into the pump. The peripheral portions of the vanes An annular skirt 5d u 82, shaft 69, bearing 55 and bearing sup- .i

. closely confront the cylindrical wall 26 of the inlet and `follow the contour of the inlet portion 26h.

Each vane `87 is arcuately curved for'eiiicient centrifugal pumping action and is also axially pitched for induced axial flow through the inlet.

The vane-s S7 have relatively deep major inner end portions and relatively shallow outer end portions. The deep inner end portions constitute about to 65% of the area of each vane and lie within the diameter of the main inlet 2d while the shallow portions span the opening into the volute `chamber 3l. The leading corners between the leading ends 87a and the bottoms 87b span the mouths of the ditfuser passages 27. The bottoms 8717 closely overlie the inlet wall 2Gb and upright peripheral ends 87C project into the gap between the end wall 46 oi `the head and the top edge 26C of the inlet. Of Course, the impeller can be inserted into the casing 25 with the head 45 and has an overall diameter less than the head. This arrangement produces high speed eiliciencies at high iiow rates and the axial pitch of the vanes produces a propeller eifect to enhance the high speed efficiency.

At high rates of flow, the pump 10 receives fuel from the sump S through the inlet 26 and through the passages 27. At such high rates of ow little or no vapor separation will occur and the pump is adapted to swallow the gases and vapors and force them through the conduit 36 at such high rates that they cannot accumulate to form a pocket or trap within the pump.

When the rate of flow through the pump is slowed down to deliver fuel at lower rates as for example, when the engine demand is lessened, the flow through the passages 27 will be reversed and vapors removed from the fuel by the agitating effect of the impeller on the fuel will flow outwardly to be discharged over the lip 29 and out of the path of the incoming fuel to the inlet 26.

Thus, at 100% pump capacity (sea level rate of ow for jet engines), the velocity in all pump passages is very high. Through the entrance part of the impeller there is practically no rotation of the fuel. As a natural hydraulic consequence, the flow of fuel through the inlet diffuser is inward from the tank to the impeller. Velocities are too high for separation of bubbles at any point in the pump. y l

At intermediate altitudes (20,000 to 30,000 feet altitude), the jet engine demand may be reduced from 45% to of maximum pump capacity. Flow velocities in the `pump are reduced accordingly, and the fuel rotates `immediately upon entering the impeller. The combination of reduced inlet velocities and fuel rotation brings about a reversal of flow through thediuserpassages 27.

At high altitudes, the `jet engine fuel demand may be reduced considerably below 40% of the pump capacity and flow through the pump is reduced to such an extent that maximum rotation and centrifuging of the fuel occurs.

The rate of climb of the aircraft and the degree, if any, of pressurization of the fuel tank, will vary widely with different types of aircraft so that to meet different specifications such as increased vapor removing capacity, the impeller 3S of Figures 5, 6, and 7, may be substituted for the impeller 14. The impeller 88 extends further into the pump inlet 26 to increase the size of the centrifuging chambers. The extended centrifuging chambers do not have the pumping eliiciency of the impeller 14 and for the same amount of pumping, the impeller 88 will require more power than the impeller 14. The impeller 88 has the same small diameter hub 82 as the impeller but has a hollow shank portion S9 receiving a longer mounting bolt than the bolt 79. This shank 89 is surrounded by propeller-like vanes 90 which have a screw-like configuration. Pour vanes 9@ are provided each with a substantially flat bottomed end spanning the mouth of the inlet 26 and having an edge 90a extending radially from the shank 39. Each edge 01; serves to slice liquid in the inlet and feed it to a spirally inclined wall 90b of the vane whichmerges into^an upstanding wall-"90C at .the outer periphery: of 4the-vane. The upstanding wa1l-90c is integraltwith fingersl 90d which radiate `from the hub 82 .like curved teeth.

Vapor separating chambersV are provided-between the vanes-90-and 'gas bubblesVV are allowed to accumulate in greater quantity without interfering vwith the pump ow. These gas bubbles will be ejected through the passages 27..more effectively than by the impeller 14.

It will be noted` that the impeller vanes` 87 and 90` span the-innerl ends of the `passages 27 at a diameter which is approximately equal to the main inlet diameter 26. Since liquid entering the pump is picked up by the propeller part or pitched par-t of the vanes, at high rates of flow the angle of lea-d of the propeller part is about equal to the angle of advance of the liquid about to enter thefpassages 27. The liquid, at this high entrance velocity, does not immediately start revolving with the impeller and the non-revolving liquid tends to enter the passage in a direction parallel to the face of the vanes. non-revolving liquid passing-into the impeller at high velocity with respect to the impeller vanes, does not have sufficient rotation to'be centrifugally discharged outwardly through the passages 27. This high entrance velocity of the liquid creates a reduction in pressure at the passages 27 thereby drawing lthe' liquid'inwardly into the pump.

Thus, at high rates of ow, there is a minimum centrifugal force effect and a minimum time delay within the impeller to cause centrifugal separation and the gathering of large gas bubbles. There is-also a sufficient inlet velocity to draw the fuel through the passages 27 and augment the feed from the inlet 26.

"When the ow through the pump is reduced, the velocity through the impeller'passages is proportionately reduced and there is an accompanyingtincrease in the rotative speed of the liquid'as it becomes enclosed between the, propeller-shaped entrance vanes. This increase of rotating liquid spee-d increases the `centrifugal force outwardly in the liquid to bring about an outward flowfof liquid through the-passages 27. Further, at `the reduced rates of flow inthe pump, Vthere is an accompanying time delay within the impeller passages which gives more time for the centrifuging of bubbles andthe merging of many small bubbles into a fewer number of larger ones. When the volume of gas or the rate of bubble accumulation is normal, ythe outward liquid ow through the inlet 26 sweepsrthe .bubbles outwardly through the passages 27l to prevent gas accumulation which will interfere with normal pumping. As the flow through the pump, decreases -to very small quantities` in proportion to the full capacity ofthe pump, the centrifugal and vapor sweeping factors near the pump entrance become increasingly active to prevent-air or gas binding.

Fuel under pressure in the volute 31 is held through f the hole 52 Vinto the groove 51 and thence through the hole 53 to. flood thecasing 13 thereby cooling the motor and lubricating the bearings 55 and 68 with the fuel being pumped.

The pump -can be further modified to increase its vapor separatingvcapacitybythe addition of more power to accommodate the -increased vapor separation power demands as shown in FigureS. The modified pump 100 of Figure 8, includes the same mounting base and pump casing part 11 as the pump 10 and common parts of both pumps havef been marked withthe same reference numerals. The pump 100, however, includes a diffuser type The The member-101, however, has a thicker topwall 104 than the-wall 43j ofthe part 12 and this `.thicker wallhas diffuser passages 105. These diffuser-.passages '105 have radial portions 10541 discharging through the cylindrical periphery 28 of `thelpump casing 25 at the top ofV the casing and have rtapered inner portions 10Sb` sloping axially downward and radially inward from the inner ends of the. portions 105a to provide inlet ends in the bottom face of the head portion 106 of the member 101. This head portion 106 fits through the aperture 40 in the top of the pump casing` 25 in the same manner as the head portion 45 of the member 12.

The diffuser passages 105, as best shown in Figure 9, are separated by ribs 107. These ribs or vanes 107 have side walls shaped so that the passages 105 are, in effect, tangential gaps designed for centrifugal discharge. These passages have inner ends in advance of the outer ends so as to diffuse the centrifugally whirling flow into a lateral outward ow at relatively high velocities.

It will be noted that theinner or feed ends of the passageway portions 105b, are at a diameter smaller than the diameter of the inlet 26 so as to receive fluidfrom the impeller 103 which 4is rotating at a relatively high speed effected by a full forced rotation from the impeller vanes. In addition, the fluid is under a positive pressure resulting from the pumping effect of the propeller action of the vanes and the centrifugal force of the impeller vanes.

The impeller 103, as best shown in Figures 8 and 10, is similar to the impeller 88 but has five screw vanes 108. These vanes are spiralled orhelically arranged around the central post 109 which receives the mounting bolt 79. The vanes 108 have substantially at forward lower ends with sharp end edges 108a adapted to slice into the liquid in the inlet 23 and raise this liquid along-the top helical faces 108b of the vanes to the vertical faces 108C which depend from the fingers 108:1. The impeller 103 functions in the same manner asthe impeller 88 except that it has an additional vane for inducing vapor separation. The five vanes accelerate the liquid axially and discharge it centrifugally into the volute of the pump. The rapid axial acceleration sweeps bubbles to the diffuser passages 105b. As indicated, these passages have inlet ends positioned at the terminal end of the impeller cavity where the fluid is always rotating at a high speed and is under a positive pressure. The vapors will be swept through the passages 105b into the passages 105a and discharged radially from the pump.

Since vapor separation involves consumption of energy, the motor 102 is larger than the motor of the pump 10 so as to be capable of driving-the impeller at high speeds even under the increased load imparted by vapor separation. Thus, the pump 100, while still having the basic housing component 11 as the pump 10, has lan added vapor diffuser and a vapor separating impeller for coacting with the diffuser to enhance the high altitude performance of the pump. Ther larger motor 102 can also be used with the four-vane impeller 88.

The telescoped impeller hub,fmotor shaft, shaft bearing, and bearing support, for the pumps 10 and 100, will provide a firm stable impeller support'withina very compact area. The thrusting of the impeller shoulder against the end face of the shaft enhances the rigidity of the assembly. The contacting thrust faces are of relatively large diameter compared with the hub so that tilting or cocking of the impeller is prevented even if the hub has a free fit in the shaft. This makes possible an impeller of smaller overall diameter since the mounting screws 79 can be very thin or can be quite-short in-the type of impeller indicated at 14 for the pump 10.

If desired, as shown in Figure 11, the mounting bolt 79 for the impeller such as the impeller 103, can be replaced with a bolt 110 extending through thehollow shaft. lIn this Yarrangement the impeller hub 82 is internally threaded yat 111 to receive the threaded end of the bolt llitl and a cover disk 112 overlies the upper end of the motor shaft o9. The head of the bolt is bottomed on this disk. Notches 113 are preferably provided in the end of the shaft under the disk lf2 to receive a lock wire (not shown) to hold the bolt Mtl. The bolt Ill@ will draw the head of the impeller tightly against the gasket S6 in the same manner as described in connection with Figure l. Here again, the impeller hub, motor shaft, bearing, and bearing supports are nested and telescoped while the shoulder of the impeller is firmly bottomed on the shaft.

As illustrated in Figure 12, the pumps of this invention are built up from a basic mounting plate and pump casing part lll which can selectively receive a` high flow rate impeller 14 with a moderate vapor separating capac ity, a lower iiow rate impeller 33 with a higher vapor separating capacity or an impeller 103 with a still higher vapor separating capacity. Further, an end head part l2, or a diffuser end head part 101, can be used in the pump. In addition, the pump can have any one of a number of motor components including small motors such as L33 and a larger motor such as 102.

Prom the above descriptions it should thus be understood that this invention provides pump assemblies which can be selectively built up from basic parts to meet various specifications and thereby eliminate wastage of power. The pumps of this invention have secondary inlets which function to augment intake at high rates of iiow and which will serve as diffuser outlets for bubbles of gas or vapor at lower rates of new through the pump.

The pumps can be equipped with secondary diffuser outlets to cope with severe vapor conditions to the end that `fully liquid fuel in desired amounts will always be delivered regardless of altitude. The motors and impellers of the pumps of this invention are adapted to be changed or substituted to meet requirements of different engine fuel systems. Thus, the invention provides basic pump components which can be usedtin various combinations to modify the pump characteristics.

lt will be understood that variations and modications may be effected withoutdeparting from the scope of the novel concepts of this invention. t

I claim as my invention:

l. A pump and motor assembly which comprises an open top main pump casing defining an axial inlet, an annular volute chamber, an impeller chamber between the inlet and volute chamber and a peripheral `outlet from said volute chamber, means for mounting said casing in a tank, an end head detachably mounted on the pump casing and having an integral thickened central portion projecting through the open top of said casing into said volute chamber to form a cylindrical inner periphery therefor, a bearing carried by said central portion of said head to lie wholly within said casing, a motor de- `tachably mounted on said end head having a drive shaft rotatably supported in said bearing, and a pump impeller having a hub removably mounted in the end of said drive shaft and surrounded by said bearing, said impeller having pumping vanes underlying said end head in said impeller chamber for pumping iiuid from the inlet to theperipheral outlet.

2. A pump assembly comprising an open top caslng providing a lower sump chamber, an upper volute chamber, an intermediate irnpeller chamber and an aXial inletfrom said sump chamber into saidimpeller chamber, an end head closing the open top of said casing and extending into said volute -chamber to define an inner annular periphery thereof and a unidirectionally driven impeller underlying said end head and having vanes in said impeller chamber inducing liquid flow through said inlet to said volute chamber from said sump chamber, there being outwardly diverging diffuser passages radiating from said impeller chamber to said sump chamber, whereby at low rates of liquid flow rotation of said impeller causes a gas flow outwardly through said diffuser passages and at high rates of liquid iiow rotation of said impeller in the same direction induces liquid flow inwardly through said diffuser passages to supplement liquid flow through said inlet.

3. A pump and electric motor assembly adapted for mounting on a cell wall to be submerged in the contents of the cell which comprises a main casing part having a mounting base adapted to span an opening in a tank wall and having fasteners around the periphery thereof for suspending the plate on the tank wall, said plato having a localized depressed portion providing a sump beneath the tank wall, an annular pump casing deiining a volute chamber surrounding an impeller chamber with a bottom` inlet, legs supporting the pump casing in spaced relation above the bottom of the sump to hold the bottom inist of the casing above the sump wall, an end head removably mounted on top of the annular pump casing and having a central head portion extending into the casing to define an end for the impeller chamber, a bearing carried by said central head portion in said casing, a motor removably mounted on said end head, said motor having a shaft rotatably supported by said bearing, a pump impeller having a hub detachably connected to said shaft and a plurality of vanes extending into the mpeller chamber between the inlet and the volute chamber, said impeller, said end head and said motor being selectively replaceable to cooperate with the main` casing part for varying the characteristics of the pump.

4. A pump and motor assembly adapted for mounting on a wall of a tank to be submerged in the contents of the tank which comprises a main casing part having a mounting plate on the bottom thereof adapted to span the opening in a tank wall and underlie the tank, said mounting plate having a localized depressed portion forming a sump, a pump casing carried above the depressed localized portion of the mounting plate by a plurality of supporting legs, said pump casing having an axial passage therethrough with'a pumping chamber surrounding the passage in full communication therewith around the entire periphery thereof, a peripheral outlet conduit for said pumping chamber, said conduit having a terminal end discharging through the mounting plate, coupling means coacting with the terminal end of the conduit to receive fluid therefrom, said pump casing having a generally cylindrical bottom inlet and a ring of passages surrounding said inlet and radiating therefrom to the periphery of the pump casing, an end head removably mounted on said annular pump casing .having a por tion extending into the axial open top of the casing to form an inner peripheral wall portion for the pumping chamber, a bearing carried by said end head in said pump casing, a motor casing removably mounted on said end head, a motor in said casing having a hollow shaft rotatably supported by said bearing, an impeller between the inlet and pumping chamber of the pump casing having a hub extending into said motor shaft and surrounded by the said bearing, and bolt means uniting the impeller hub and motor shaft.

5. in a submerged type vapor separating booster pump assembly, an open topped main pump casing having means for attachment to the wall of a fuel tank, said casing defining an axial inlet, an annular volute chamber and an impeller chamber between the inlet andthe voiute chamber, an end cover on said pump casing having a head portion extending into the open top of the casing on the side thereof remote from the inlet, said head portion having a bearing iixedly mounted therein, a motor casing removably mounted on said end head, a motor in said casing having a hollow shaft extending into said end head and rotatably mounted in said bearing, an impeller under lying said end head in said impeller chamber and having a hub extending into said hollow motor shaft, and a mounting bolt extending through said hub and affixed to said motor shaft for uniting the hub and shaft.

6. A submerged fuel booster pump and motor unit 0r the likeswhich comprises a main casing art having a mounting plate.defning an inlet sump and carrying an annular volute casing with an axial passage therethrough providing a bottom inlet communicating with said sump, an open top and an impeller chamber between the inlet and volute chamber, a peripheral outlet conduit on said casing having a terminal end discharging through the mounting base, a cover removably mounted on said volute casing having va head portion extending through the open top of the casing to form an inner peripheral wall portion for the volute chamber, a bearing car ed by said head portion, a motor casing detachably mounted on said cover, a motor in said casing having a holiow drive shaft rotatably supported in said bearing in said pump casing, an impeller having a hub extending into said hollow motor shaft surrounded by said bearing and a plurality of vanes in said impeller chamber, radial pa ge means insaid volute casing surrounding the pump inlet at the -feed ends of the impeller venes, and said impeller vanes being shaped to develop a reduced pressure Zone at the inner ends of said passages vto `draw liquid through the passages only when the vanes deliver fluid at a high rate through the inlet and to develop positive pressure at said passages when delivering a low flow rate to discharge uid outwardly through the passages.

7. A pump assembly which comprises a main pump casing part defining an annular pumping chamber surrounding an axial passage therethrough, one end of said passage providing a pump inlet communicating with said pumping chamber, `openings in said casing joining the inlet with the periphery of ther casing downstream from the entrance mouth to the casing at a diameter substantially the same as the entrance mouth, an end cover detachably mounted on said pump casing and projecting into the open top of the casing, a bearing carried by said end cover in said casing, a motor casing detachably mounted onsaid end cover, a motor in said casing having l a 4hollow shaft rotatably supported in said bearing, said hollow shaft having an end surrounded by the bearing, a pump impeller having a head underlying said end cover in close running clearance relation therewith and a hub projecting from said head into the open end of the pump shaft, a key uniting the hub and shaft for co-rotation, a bolt extending through said hub, and nut means bottomed on said shaft receiving said bolt in threaded relation therethrough to unite the impeller with the shaft, and vanes on Asaid impeller extending into the inlet adjacent said openings to coact therewith for selectively drawing fluid into the pump or ejecting bubbles from the pump.

8. A pump and motor assembly which comprises a motor casing, end heads on said casing providing opposed recesses, bearings mounted in said opposed recesses, ahollow motor shaft rotatably supported in said bearings having an end portion communicating through one end head, a motor armature on said shaft, a motor field carried by the casing surrounding said armature, a pump casing detachably mounted on said end head receiving the hollow `shaft portion therethrough, a pump impeller in said pump casing having a hub extending into said hollow shaft, a key uniting the hub `and shaft for tto-rotation, and a bolt connecting the hub and shaft effective to draw the impeller tightly against the end of the shaft.

9. A pump and motor assembly which comprises a motor casing, a motor in said casing, a hollow shaft in said motor, a removable end head on said casing rotatably supporting one end of the shaft, said hollow motor shaft having an internally splined portion and a shoulder adjacent said portion, a nut bottomed on said shoulder and splined to said splined portion to prevent relative ro tation between the nut and shaft, a pump impeller having Cil 1.2 a hub extending yinto the shaft and surrounded by said bearing, and a mounting bolt extending through said impeller hub and threaded into 'said nut to secure the impeller on the end of the shaft.

10. A pump and motor assembly comprising a motor casing, a motor in said casing, end heads on said casing providing opposed recesses, bearings in said recesses, a hollow motor shaft rotatably carried by said bearings, one of said end heads having an aperture therethrough receiving an open end of the motor shaft, a pump having hub inserted through said aperture into the motor shaft, a liey uniting the hub and motor shaft, a cover on the opposite end of the shaft, and a bolt bottomed on said cover and extending through said shaft into threaded engagement with said hub to unite the impeller with the shaft.

1l. A pump and motor assembly which comprises a main pump casing having an axial passage therethrough surrounded by an annular pumping chamber, one end of said passage forming a pump inlet, passages radiating from said inlet to-the periphery of the casing adjacent the said one end, the other end ofthe casing receiving an end head therein, said end head having vapor diffusing passages connecting the central portion of the casing at a diameter inside of the pump inlet diameter with the periphery of the casing, a pump impeller rotatably carried by the end head and having pumping vanes connecting the inlet with the pumping chamber, said pumping vanes having vapor separating portions for positively ejecting vapor laden fluid through said diffuser passages before the fluid reaches the pumping chamber, and said vanes coacting with the passages adjacent the inlet end of the pump to draw fluid through said passages into the pump at high rates of flow and to eject duid from the pump at low rates of flow.

12. A pump impeller which comprises a hub, a plurality of fingers radiating from the hub, a post depending from the hub, vanes surro-unding the post and depending from the lingers, and said vanes having screw-like leading ends radiating from the post, helical portions entwined about the post and upstanding centrifugal pumping portions merging into the lingers, said leading ends adapted to slice olf fluid from a pond, said helical portions adapted to advance the sliced 0H fluid to the pumping portions, and said pumping portions adapted to centrifugally discharge the fluid.

13. A pump and motor unit which comprises a pump casing, a motor casing, an end head between the casings, a bearing carried by said end head, a hollow open ended motor shaft supported by said bearing, an impeller in said casing having a hub projecting into the open end of the shaft and a shoulder underlying the shaft, a draw bolt urging said shoulder into thrusting relation with the end of the shaft, land said open end of the shaft, said hub, said bolt and said bearing being in telescoped relation.

References Cited in the file of this patent j UNITED STATES PATENTS 1,651,881 Frickey et al Dec. 6, 1927 42,130,583 Fosnot Sept. 20, 1938 2,368,529 Edwards Jan. 30, 1945 2,459,036 Lipe et a1 Jan. l1, 1949 2,581,828 Adams Jan. 8, 1952 2,581,872 Morrison Jan` 8, 1952 2,669,187 Guyer Feb. 16, 1954 2,671,635 Willi Mar. 9, 1954 2,704,516 Mock et al. Mar. 22, 1955 FOREIGN PATENTS 597,402 Great Britain Ian. 26, 1948 

